Best amp for Dynaudio C4

McIntosh 1.2kw is probably the best value/performance amp(these are monos). There are budget oriented choices as well depending on what you need to accomplish. For even more superior luxury if you use Mac C4* preamp with multiple outputs, you can actually bi-amplify with Mac components and have 1.2kW Mac stack per each speaker. Prepare to allocate a dedicated power line as important necessity just for amps.
As to stereo vs. mono I wouldn't realy care. On the first hand 600W per side might not be enough, but if driven by recommended Mac, it's the whole different beast... If biamplified with the same(two monoblocks per each speaker), you can place the system inside the movie theater.

I've read where the Octave amps (e.g., top of the line integrated with super black box) are hard to beat, and Dynaudio is the official NA distributor. I'm very happy with my VAC 300.1a tube amp, which I imagine would pair well with Dynaudios (I have auditioned C series speakers but not with VAC amps).

As an Octave V70SE and Dyn C1 owner I would say the V80 integrated with Super black box would work well but in my opinion not at real high volumes. Octave has the re290 which is designed around the KT120 tubes which would be better. Depending on your budget the mre130 mono blocks would be killer especially if you were to add the black or super black box to either re290 or mre130 amps. The black box just adds capacitance for a lower noise floor - better dynamics and a little more headroom. Something to consider with the mono blocks you have twice as many output tubes which put out a lot of heat. Jubilees would be the best but we are talking $67K for those bad boys. They drove the Consequence Ultimate Editions quite well and a little bit of overkill for the C4's in my opinion.

That all being said Dynaudio also distributes the T + A brand which is also very good match for Dyns although I have never heard them. But looking at all the pictures from the last 2 RMAF shows Dyn has been pairing up Octave with most of the Dyns.

Best of luck in your search and in my personal opinion the C4's are the best speaker I've ever heard - just don't have the room for them or I would own them.

Thanks for all your wonderful advice !!